Background: Despite the favorable history of surgical approach to repair secundum type atrial septal defects (ASDs), the transcatheter closure has increasingly become the preferred strategy because of its relatively high efficacy and lower morbidity compared to surgery in selected cases. However, there is some controversy around the preferred strategy and long-term complications of device closure of large ASDs. Here, we evaluated the early and midterm outcomes of adults with large ASDs who underwent transcatheter device closure with devices larger than 28 mm. Methods: A prospective single-center study was conducted encompassing all the patients who were 18 years of age or older and underwent device closure for secundum type ASD from 2006 to 2014 with device size of >28 mm, and early and midterm follow-up data were assessed. Results: The procedure was successful in 93.6% of the scheduled patients. Two and a half percent had nonsignificant residual shunt. Immediate device migration occurred in one patient (1.2%) who underwent surgical retrieval and defect closure. One case of device thrombosis (1.2%) was seen 1 month after the procedure who had successful medical treatment. There was a case of device erosion 1 month after the procedure referred for the surgery. Mild postintervention pericardial effusion was seen in 16.5% and reduced to 7.6% in the first outpatient visit. Conclusions: The study demonstrated that the vast majority of anatomically suitable large ASDs could be closed by using the transcatheter technique with a low complication rate. Therefore, the transcatheter closure could be recommended as the first-line strategy in adults with large ASDs. However, meticulous preprocedural imaging and evaluation by experts are necessary before scheduling patients with large ASDs for the percutaneous alternative.

Atrial septal defects (ASDs) are regarded as one of the most prevalent congenital heart diseases, with an estimated incidence of one in every 1000 live births. Secundum type ASDs with an incidence rate of 22% are the second most common form of congenital heart disease among adults.[1],[2],[3] If left untreated, the right ventricular (RV) volume overloading and failure, pulmonary hypertension, and other complications would ensue.[4],[5]

Despite the longer history of surgical closure to address secundum ASDs, the transcatheter closure has become an increasingly popular strategy due to its relatively high efficacy and lower morbidity.[6],[7] In spite of the potential benefits of transcatheter ASD closure, there are rare but serious complications such as valvular compression/perforation, arrhythmias, or device embolization. The rate of complications is reported to increase when larger devices are necessary.[7] However, some recent studies have indicated the safety and efficacy of transcatheter method even for considerably large defects. In the present study, we aimed to investigate the safety and feasibility of the interventional ASD repair using large devices and evaluated the early and midterm outcomes of adult patients who underwent device closure with devices of >28-mm waist diameter.

Methods

Study design

A prospective single-center study was conducted encompassing all the patients who were 18 years of age or older and underwent device closure for secundum type ASD from 2006 to 2014 with device size of >28 mm. Written informed consents were obtained, and the Institutional Ethics Committee approved the study protocol. The inclusion criteria included patients above 17 years of age with a secundum type ASD, and a left-to-right shunt with a Qp/Qs of ≥1.5:1 or the presence of right-sided chamber enlargement and volume overload whose ASD deemed suitable for device closure using transesophageal echocardiography (TEE). Exclusion criteria consisted of evidence of irreversible pulmonary hypertension and rim insufficiency precluding percutaneous closure.

Echocardiography protocol

All patients had comprehensive transthoracic echocardiogram (TTE) and TEE to ASD closure. RV size and function and pulmonary arterial pressure were measured according to the American society of echocardiography guidelines.[8] Anatomic features of the ASD were evaluated and the size was determined based on the largest diameter after assessing multiple views. Rims of the ASD were carefully evaluated with special attention given to anteroinferior and posterosuperior rims on the 4-chamber view, aortic (anterosuperior), and posteroinferior rim on the 45° mid esophageal view and inferior vena cava/superior vena cava rims on the 90° TEE views. Rims shorter than 5 mm in length were considered deficient.[9] All the patients had intraprocedural TEE performed. Full TTE evaluation was then performed 24 h after the procedure and on successive outpatient visits. The first clinic visit was scheduled in the 1st month following the procedure, and then, every 6 months with the physical examination, electrocardiography (ECG) and TTE were performed in each visit.

Procedure characteristics

ASD closure was done under sedation and was TEE guided. Balloon sizing with a 35 or 40-mm compliant balloon was performed to achieve stop flow. Fluoroscopic and echocardiographic measurements of stretch diameter were then performed. The device was chosen 2–4 mm larger than the measured stretch size considering redundancy and length of the rims with greater oversizing for the ASD s with more redundant or shorter rims.

All the patients had intraprocedural and postprocedural ECG monitoring for 24 h and postprocedural 12-lead ECG and TTE were performed. No persistent or significant arrhythmias or heart block was detected in our adult patient series.

The procedure was regarded as successful when all of the following conditions were met:

Successfully delivered ASD device with no periprocedural complication

Well-positioned ASD occluder as confirmed by intraprocedural TEE and TTE 24 h after the procedure with no compressive effect on adjacent structures, no clot on the device or significant residue

Seventy-nine patients, who met the inclusion criteria, were studied. All had a significant left-to-right shunt with various degrees of RV dilation or dysfunction according to TEE performed before the procedure.

Reference characteristics of the patients are illustrated in [Table 1]. The majority were female (68.4%), with a mean age of 35.7 years. The right ventricle was severely dilated in 69.6% of the patients, and RV function was normal in only 20.3% of patients. Mild, moderate, and severe RV dysfunction was reported in 53.2%, 24.1%, and 2.5% of patients, respectively. In the majority of patients, the left ventricular function was normal (77.2%) with mild, moderate, and severe dysfunction was seen in 12.7%, 8.9%, and 1.3% of patients, respectively [Table 2].

The mean ASD size was 24.8 mm (maximum 40 mm), two cases had two ASDs, and another had small fenestration (3 mm) with 4-mm distance from ASD. Before ASD closure, complete invasive hemodynamic and oximetry data were obtained. Rims characteristics are presented in [Table 3].

The procedure was failed in four patients (5.1%). In three patients, the device was deployed but not released due to device malalignment on interatrial septum.

Immediate device migration occurred in one patient who underwent surgical retrieval and defect closure. One case of device thrombosis was seen 1 month after the procedure who had successful medical treatment. One patient with a 33-mm device developed device-related cardiac erosion after 1 month presenting with cardiac tamponade. The patient underwent surgical retrieval of the device, cardiac perforation repair, and surgical closure of ASD. Postprocedural pericardial effusion was seen in 16.5%, was mild in all cases, and reduced to 7.6% at the first outpatient visit. No other major or minor complication occurred during the procedure or within 24 h after discharge.

Superior rim deficiency was more common in patients with failed rather than successful closure. (100% vs. 62.7%), although it was not statistically significant. Deficiencies of the remaining rims were not associated with procedural failure [Table 4].

According to echocardiography during outpatient visit, 32.9%, 43%, and 63.3% of patients had improved RV size, function, and pulmonary hypertension, respectively.

Discussion

For more than half a century, surgical closure of large ASDs has been performed and has now achieved a very low mortality rate and optimal outcomes. The presence of a large left-to-right shunt in adults with ASD is regarded as an indication for surgical closure to improve survival, relieve symptoms, restore normal exercise capacity, chamber enlargement, heart failure, and pulmonary hypertension.[8],[9],[10],[11],[12],[13],[14] Although the operation is low risk and often successful, there is a reported mortality rate of about 1.2%–3.3% in adults and some inevitable morbidity linked to cardiac bypass, atriotomy, and surgical scars and the need for staying in Intensive Care Unit in 9%–13% of cases. Residual shunting is also variably reported in 1%–7.8% of cases.[4],[6],[9],[12],[15]

Transcatheter closure is now becoming the first-line strategy for adult patients with secundum ASDs in whom the defect anatomy is deemed suitable during preintervention TEE.[16],[17] Obviously, there are advantages to this method including cosmetic- and scar-related issues and shorter hospital stay. However, for large ASDs, defined as those requiring devices ≥28 mm for the current study, there is some controversy over the safety, feasibility, and long-term outcomes of the transcatheter ASD closure. These defects compromise approximately 20% of cases of secundum ASD.[18],[19] The percutaneous procedure is technically demanding mainly due to aortic rim deficiency or absence, significant redundancy or marginally acceptable size of other rims, and the rims not being in the optimal alignment.[8] There are different techniques described that could be utilized to align the device in very large ASDs, particularly in experienced centers. The use of intraprocedural TEE, which is rather feasible in adults, is very helpful in accomplishing the procedure. Deficient aortic rims are very common in large ASDs and although not a contraindication for transcatheter closure might make the procedure more challenging and is reported to increase the likelihood of complications in some studies.[18],[20],[21],[22] In this study, we found no direct relationship between the presence or absence of aortic rim and procedural failure. We believe large ASD size combined with the borderline size or nonoptimal characteristics of the rims might together influence the success rate of the procedure and no single factor could be described.

In similar studies of pediatric and adult patients, Rodriguez et al. reported a success rate of 74% for large ASD transcatheter closure.[18] Du et al. reported 96% success rate of large ASD transcatheter closure compared with surgical closure with zero mortality and very low risk of complications.[19] Baruteau et al. described a success rate of 92.6% in their single-center study with device migration seen in four patients.[6]

In this study, initial device deployment was achieved successfully in 75 of 79 patients. There was an overall success rate of 93.6% with a complication rate of about 2.5% related to device erosion and migration in two patients. There was no mortality. To the best of our knowledge, although there are some experience regarding the closure of very large ASDs (i.e., device size >40 mm) globally,[8] there are not many national studies describing the experience with the use of 30–39-mm device in adults, thus making this study a basis for better planning regarding patient management and approach. Based on this single-center study, closure of large ASDs could be recommended as a safe and effective alternative to surgery in experienced hands. However, caution should be exercised, especially in regard to echocardiographic evaluations before scheduling patients, for this strategy.

Conclusions

The device closure of large ASDs, although not complication free could be performed with low morbidity and effectively in experienced centers. Patient selection based on prior assessment by experienced echocardiographers using TEE is the recommended strategy to minimalize the possibility of complications.

Rudski LG, Lai WW, Afilalo J, Hua L, Handschumacher MD, Chandrasekaran K, et al. Guidelines for the echocardiographic assessment of the right heart in adults: A report from the American Society of Echocardiography endorsed by the European Association of Echocardiography, a registered branch of the European Society of Cardiology, and the Canadian Society of Echocardiography. J Am Soc Echocardiogr 2010;23:685-713.